using System;
using System.Collections.Generic;

namespace Terminal.Gui;

/// <summary>
/// The execution state for a <see cref="Toplevel"/> view.
/// </summary>
public class RunState : IDisposable {
	/// <summary>
	/// Initializes a new <see cref="RunState"/> class.
	/// </summary>
	/// <param name="view"></param>
	public RunState (Toplevel view)
	{
		Toplevel = view;
	}
	/// <summary>
	/// The <see cref="Toplevel"/> belonging to this <see cref="RunState"/>.
	/// </summary>
	public Toplevel Toplevel { get; internal set; }

#if DEBUG_IDISPOSABLE
	/// <summary>
	/// For debug (see DEBUG_IDISPOSABLE define) purposes to verify objects are being disposed properly
	/// </summary>
	public bool WasDisposed = false;

	/// <summary>
	/// For debug (see DEBUG_IDISPOSABLE define) purposes to verify objects are being disposed properly
	/// </summary>
	public int DisposedCount = 0;

	/// <summary>
	/// For debug (see DEBUG_IDISPOSABLE define) purposes; the runstate instances that have been created
	/// </summary>
	public static List<RunState> Instances = new List<RunState> ();

	/// <summary>
	/// Creates a new RunState object.
	/// </summary>
	public RunState ()
	{
		Instances.Add (this);
	}
#endif

	/// <summary>
	/// Releases all resource used by the <see cref="RunState"/> object.
	/// </summary>
	/// <remarks>
	/// Call <see cref="Dispose()"/> when you are finished using the <see cref="RunState"/>. 
	/// </remarks>
	/// <remarks>
	/// <see cref="Dispose()"/> method leaves the <see cref="RunState"/> in an unusable state. After
	/// calling <see cref="Dispose()"/>, you must release all references to the
	/// <see cref="RunState"/> so the garbage collector can reclaim the memory that the
	/// <see cref="RunState"/> was occupying.
	/// </remarks>
	public void Dispose ()
	{
		Dispose (true);
		GC.SuppressFinalize (this);
#if DEBUG_IDISPOSABLE
		WasDisposed = true;
#endif
	}

	/// <summary>
	/// Releases all resource used by the <see cref="RunState"/> object.
	/// </summary>
	/// <param name="disposing">If set to <see langword="true"/> we are disposing and should dispose held objects.</param>
	protected virtual void Dispose (bool disposing)
	{
		if (Toplevel != null && disposing) {
			throw new InvalidOperationException ("You must clean up (Dispose) the Toplevel before calling Application.RunState.Dispose");
		}
	}
}